I built a wet cell and it was amazing how much gains I got.
my mercedes e320 went fro 18 mpg to 40!!! I had to remove it because when it got hot it would spit water out into my engine

I bought a dry cell of of ebay for $200 (I know I think I paid to much) and the car went from 18mpg up to 26.. Still pretty good if you ask me, now I bought a ford excursion with a diesel engine and I don't have much knowledge about building a DRY CELL (i imagine it cannot be that hard)...

SO my question to all you pros out there is; should I spend the time to build one? OR does anyone know a good website that has good quality dry cells (maybe a kit too) that I can buy? I don't mind paying a little extra money just as long as the kit is GOOD and that you guys have had success with it.